The use of wireless communication devices (WCDs) is becoming increasingly prevalent and popular in modern life. To provide cellular wireless communication service to WCDs, a wireless service provider typically operates a radio access network (RAN) that defines coverage areas (such as cells and/or sectors) in which subscribers' WCDs can be served by the RAN and obtain connectivity to other networks such as the public switched telephone network (PSTN) and the Internet.
A typical RAN includes one or more base transceiver stations (BTSs), each of which may radiate to define one or more coverage areas in which these WCDs can operate. Further, the RAN may include one or more base station controllers (BSCs) or the like, which may be integrated with or otherwise in communication with the BTSs, and which may include or be in communication with one or more switches and/or gateways that provide connectivity with one or more transport networks. Conveniently, with this arrangement, a WCD positioned within the coverage of the RAN can communicate with a BTS and in turn with other served devices and/or with other entities via the one or more transport networks.
In each coverage area, a RAN will typically broadcast (via, e.g., a BTS) a pilot signal that notifies WCDs of the coverage area. In operation, when a WCD detects a pilot signal of sufficient strength, it may transmit a registration message to the RAN to notify the RAN that the WCD is in the coverage area and is requesting service from the RAN via the BTS. If the request is granted, the WCD may then operate in the coverage area in what is typically known as “idle” mode, where the WCD is not actively engaged in a call or other traffic (e.g., packet-data) communication, but does regularly monitor overhead signals in the coverage area to obtain system information and page messages, as examples.